Which one of the following micro-organisms is used as a biofertilizer?

Options

A. Bacillus
B. Azospirillum
C. Pseudomonas
D. Saccharomyces

Answer

To determine which microorganism is used as a biofertilizer, we can analyze the options provided. Here’s a step-by-step solution:

### Step 1: Identify the Microorganisms
We need to look at the list of microorganisms given in the question. Common microorganisms that can be considered include:
- Bacillus
- Saccharomyces
- Azospirillum
- Rhizobium

### Step 2: Understand the Role of Each Microorganism
- **Bacillus**: This genus includes various species that are primarily used in medical and agricultural applications, but they are not specifically known as biofertilizers.

- **Saccharomyces**: This is a type of yeast, commonly used in baking and brewing (for making bread, wine, and beer). It is not used as a biofertilizer.

- **Azospirillum**: This is a genus of bacteria that is known for its role in nitrogen fixation. It is commonly used as a biofertilizer because it helps in enhancing plant growth by fixing atmospheric nitrogen into a form that plants can utilize.

- **Rhizobium**: This is another important nitrogen-fixing bacterium that forms symbiotic relationships with legumes, helping them to fix nitrogen in the soil. It is also considered a biofertilizer.

### Step 3: Determine the Correct Answer
Among the microorganisms analyzed, **Azospirillum** is specifically noted for its role as a biofertilizer due to its ability to fix nitrogen and promote plant growth. Therefore, the correct answer is:

**Azospirillum**.

### Step 4: Conclusion
The microorganism used as a biofertilizer from the options provided is **Azospirillum**.

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